Thin silicon dioxide films have a wide range of applications in the semiconductor industry. These films are conventionally formed by several methods including thermal oxidation of silicon, plasma enhanced chemical vapor deposition (glow discharge), plasma anodization and plasma oxidation. While the films formed by oxidation are often of the highest quality, this process is carried out at about 1100.degree.-1200.degree. C., too high for many applications.
A copending application entitled "Low Temperature Growth of Silicon Dioxide on Silicon" filed concurrently herewith by Kaganowicz et al. describes a process for the plasma oxidation of silicon at low temperatures, i.e. below about 300.degree. C. and preferably at about 130.degree. C. This process produces a film of silicon dioxide of good density which is characterized by an excellent silicon to silicon dioxide interface with the underlying silicon substrate. This process, however, is diffusion limited and can efficiently produce a film of silicon dioxide only up to about 100 angstroms (.ANG.) in thickness. To grow layers in excess of 1000 .ANG. in thickness, it would be necessary to substantially increase the power. As this would also increase the temperature, the process could not be carried out at temperatures below about 300.degree. C. and a principal advantage would be lost.
Plasma enhanced chemical vapor deposition, also known as glow discharge, of silane (SiH.sub.4) and an oxygen containing gas is a known process of depositing a silicon dioxide layer at low temperatures. Those of ordinary skill in the art are aware that films produced by this process have poor density and, therefore, do not meet the requirements for a dielectric material in most semiconductor applications. Efforts to improve the density of films produced by this process have principally involved increasing the temperature and/or the power. Although effective to a degree, these measures disadvantageously drive the temperature above the 300.degree. C. mark. It would be desirable, therefore, to have a process of producing silicon dioxide films at temperatures below 300.degree. C. with good density and a good silicon to silicon dioxide interface at thicknesses greater than 1000 .ANG..